Final answer:
The gene that inhibits or stops the cell cycle is the tumor suppressor gene, which codes for proteins that prevent uncontrolled cell division, playing a key role in suppressing tumor development.
Step-by-step explanation:
The type of gene that usually works to inhibit or stop the cell cycle is known as a tumor suppressor gene. These genes are essential for regulating cell division and maintaining genomic integrity. Tumor suppressor genes code for negative regulator proteins that act as a roadblock to cell cycle progression, ensuring that cells do not undergo uncontrolled division.
Some well-known examples of proteins produced by tumor suppressor genes include Rb, p53, and p21, which play crucial roles in halting the cell cycle if there are any issues detected, such as DNA damage. Without the proper function of these genes, cells may divide uncontrollably, leading to the development of tumors and cancer. Therefore, the correct answer to which type of gene inhibits the cell cycle is (1) Tumor suppressor gene.